Piezo-electric crystal apparatus



Aprii 14, 1931. A. M. TROGNER PIEZO ELECTRIC CRYSEIAL APPARK'PUS Fil edDec. 18 1928 INVENTOR.

Q MAL ETTORNEY Patented Apr. 14, 1931- U ITED STATES recent PATENTOFFICE I ARTHUR M. TROGNER, OF EAST ORANGE, NEW JERSEY, ASSIGNOR 'I'OWIRED RADIO,

' INC., OF NEW YORK, N. Y., A. CORPORATION OF DELAWARE of the crystalprotected against chipping or PIEZO-ELECTRIC CRYSTAL APPARATUSApplication filed December 18,1928 Serial No. 326,813.

' My invention relates broadly to piezo electric crystal apparatus andmore particularly toa holder for piezo electric crystals.

One of the objects of my invention is to provide a construction of piezoelectric crystal holder in which a piezo electric crystal element may behoused for vibration with substantially no restriction, with the edgesdestruction.

Another object of my invention is to provide a construction of piezoelectric crystal holder in which various sizes of piezo electric crystalelements may be housed for vibration with substantially no restraint fordelivering maximum piezo electric eli'ect at-the terminals of theholder.

A further object of my inventio'h is to provide a construction of piezoelectric crystal holder in which a piezo electric crystal element may becompactly arranged within an insulated frame member where the sidesthereof are formed to'engage edge supporting means while the top andbottom of the piezo electric crystal holder serve as contact electrodesfor the crystal within the holder.

A still further object of my invention is to provide a construction ofcentering member above a piezo electric crystal element for guiding apiezo electric-crystal element during the oscillatory motion thereof andfor protecting the piezoelectriccrystal element against breakageduringshipment thereof.

crystal apparatus illustrated in Fig. 2; Fig. 4 is afragmentary-perspective view of'a por-.

tion of the insulated holder illustrating the position of one of thesockets which support the centering device or removable bridge in thepiezo electric crystal holder and Fig. 5

is a perspective view of the centering device or removable bridgeemployed in the piezo electric crystal apparatus of my invention.

Piezo electric crystal holders may be broadly divided into two classesaccording to the usage to which the crystals are to be placed. The firstclass is that of transmitter crystals where the crystal is required tofurnish considerable power and hence must be fairly large and held inthe holder in such a manner as to offer the least possible detriment toits action. The second class might be called frequency indicating inthatthe crystal is mainly used only to maintain the oscilla-' tionsconstant in a relatively feebly oscillating circuit. The crystaltherefore need not be as large as in the previous class and the holdersneed not be as elaborate in the crystal holding features.

' The crystal holder of my present invention is more particularlyadapted for the frequency indicating class. The crystal holder comprisesan insulated body structure having top and bottom cover plates betweenwhich the piezoelectric crystal is mounted. The frame of the piezoelectric crystal holder is provided with longitudinal projections onopposite sides which serve to support the crystal holderin groovesformed in a supporting member. The crystal retainer comprises a flatmember or removable bridge apertured at its center which extendsparallel to the upper electrode of the piezo electric crystal element.The flat member has tongues on each side thereof which may be disposedat an angle to the plane of the surface of the flat member andproject'into sockets in the within the holder that the probability ofbreakage of the crystal in shipment or use is substantially negligible.

Referring to the drawings in more detail, reference character 1designates the frame of the piezo electric crystal holder provided withlongitudinally extending projections 2 posite sides of the piezoelectric crystal at the oppositesides thereof which fit into a groovedsupport represented at 30. The

rame is closed at its top and bottom by means of plates 3 and 4. Screwmembers 5 and 6 are secured to diagonally opposite corners of the plate3, and two corresponding screw members disposed at the other two cornershold plate 4 to frame 1; these'screws enter the insulated framestructure, as represented at 5a and 6a, in such manner that the capacityloss between the plates is substantially reduced since the screws ofopposite plates are not directed towards each other on the same cornerbut are on different corners of the inplate or bridge 12 in the desiredposition within the holder. The retaining plate 12 is centrallyapertured as represented at 14 and has projecting from opposite sidesthereof the tongues 15 and 16 angularly disposed with respect to theplane of the plate or bridge 12 to enable the plate to be centeredwithin the piezo electric crystal holder for.

preventing excess or undesired movement of the plezo electric crystalwhlch is represented at 10. An electrode 9 is employed in contact withthe upper surface of the piezo electric crystal 10, which electrode isprevented from moving beyond a given limit established by 5 vthe planeof the retaining member or bridge 12. Electrode 9 is connected through aflexible lead 11 with the upper cover plate 4 which serves as oneelectrode for establishing connection with the piezo electric crystalelement within the holder.

Gonnection is established with. the plate members 3 and it by. a deviceshown at 20 having arms 21 and 22 which embrace the op holder andestablishfrictional contact .with plates 4 and 3, respectively..Flexible" strap *member 23 which houses the flexible conductricalconnection with the contact arms 21 are much thinner, are employed theretain to hold low frequency crystals with the retaining member orbridge 12 maintained in posltion by the proper length of arms 15 and 16.When high frequency crystals, which ing member 12 must have supportingarms which aresubstant'ially longer than the arms when cut for crystalsof greater thickness.

. It will be observed that the-bridge member acre 12 is easily removableand that for each holder there may be provided a plurality of bridgemembers having arms of different lengths, which will be easilyinterchangesible to use this type of holder as a universal crystalholder, simply substituting the bridge member corresponding to a giventhickness of crystal, instead of requiring a separate holder for eachthickness of crystal. It will be observed that no restriction is placedupon the piezo electric crystal element 10 as to its natural vibrationcharacteristic, for there is a sufficient gap between the retainingmember 12 and the upper electrode 9 of the piezo electric crystalapparatus to allow free movement of the piezo electric crystal element10 and the securing therefrom of maximum piezo electric effect. However,under conditions of excess movement of the crystal, such as might occurwhen the crystal holder is subjected to shock or I rough handling duringshipment, breakage of the crystal is prevented by prevention ofdisplacement of the crystal beyond a safe limit.

,While I have described my invention in a certain preferred embodiment,I desire that.

it be understood that no limitations upon my invention are intendedother than are imposed by the scope of the appended claims. What I claimas new and desire to secure by Letters Patent of the United States is asfollows:

insulated frame structure, a plurality of 1. In a piezo electriccrystalapparatus", an

metallic plates forming walls closing opposite sides of said framestructure, a piezo electric crystal element having one'of its facesresting in contact with one of said plates,-anupper electrode resting incontact with the other face of said piezo electric.

crystal element, and a removable retaining bridge member extendingsubstantially parallel to said electrode and supported from oppositepoints in said frame structure for preventing. excess movement of saidpiezo electric crystal element within said apparatus.

' 21 A piezo electric crystalapparatus comprising an insulated framestructure, 'metallic plates forming walls closing opposite sides ofsaid-frame structure, a piezo electric crystal'element having one of itsfaces resting in contact with one of said plates, an electrode restingin contact with the opposite surface of said piezo electric crystalelement, and a removab'le retaining bridge member extending ina planeparallel to but spaced from said electrode for preventing excessmovement of said piezo electric crystal element with said apparatus. 7

- preventing excess movement of said piezo electric crystal elementwithin said frame structure; r

4. A piezo electric crystal apparatus comprising a frame structure ofinsulating material, metallic plate members closing the top and bottomof said frame structure, a piezo electric crystal element having one ofits faces resting in contact with one of said metallic plate members, anelectrode resting in contact with the opposite face of said piezoelectric crystal element and a removable retaining bridge membersupported from the opposite interior walls of said frame structure andhaving a portion thereof extending in a plane substantially parallel tothe upper surface of said electrode for preventing excess movement ofsaid piezo electric crystal element within said frame structure.

5. piezo electric crystal apparatus comprising a frame structure ofinsulating material, metallic plate memberslclosing the top and bottomof said frame structure, a piezo electric crystal element having one ofits 'faces resting in contact with one of said j metallic plate members,an electrode resting in contact with the opposite face of said piezoelectric crystal element, a retainer member comprising a central portionsubstantially conforming in contour to the contour'of said electrode,tongues extending from opposite sides of said central portion, saidtongues projecting into sockets formed in the opposite interior walls ofsaid frame structure for maintaining said retainer member in posia tionabove said piezo electric crystalelement in such manner as. to be easilyremovable;

from said sockets and-preventing excess displacement of said element;

'6. piezo electric crystal apparatus com-- prising a frame structure ofinsulating material, metallic plate members'closing the top and bottomof said frame structure, a piezo electric crystal element having .one ofits faces resting in contact with one of said metallic plate members, anelectrode resting in contact with the opposite face of said piezoelectric element, a removable retainer mem ber supported by said framestructure and extending to a position immediately above said electrode,said retainer memberbeing centrally apertured to permit the passage of aconnection from said electrode to the upper; i 5 metallic plate memberwhile preventing excessimovement of said piezo electric crystal elementwithin said frame structure.

7. In a universal piezo electric crystal holder, a frame structure ofinsulating material, metallic platemembers closing the top and bottom ofsaidframe structure, a removable piezo electric crystal having one ofits faces resting in contact With one of said metallic plate members, anelectrode resting in contact with the opposite face of said piezoelectric crystal element, said frame structure having sockets inoppoiste points thereof, and a removable bridge member having a flatportion and supporting arms adapted to engage said sockets, the arms ofsaid bridge member being of length conformable to the thickness ofcrystal employed,

whereby said bridge member is supportedadjacent to said electrode: forpreventing excessive movement of said crystal.

" ARTHUR. M. TROGNER.

